My earlier U.S. Pat. No. 4,681,401 issued on Jul. 21, 1987, and U.S. Pat. No. 4,969,713 issued Nov. 13, 1990, disclosed effective improved thin surface marking strips for adhering to a road surface or the like embodying somewhat flattened wedges or blocks having retro-reflective material and of preferably substantially trapezoidal shape in longitudinal vertical section (longitudinally of the strip) with rather critical separations between the wedges relative to height-width of the wedges to obviate shadowing effects, as in sunlight, to provide improved daylight observation, and to increase effectiveness and life, particularly under conditions of rain-covered surfaces and snow. Earlier art dealing with this type of technology is disclosed in U.S. Pat. Nos. 4,388,359; 4,236,788; 4,069,787; 4,040,760 and 3,920,345.
There are occasions where the light from a vehicle or other source incident at relatively low angles to the traveling or other surface carrying the reflective strips does not come from the preferred, intended or usual directions longitudinally along the marker strip, but, rather, from different azimuthal directions about the strip. Some of the prior configurations of the retro-reflective strips of the above-referenced patents will provide some useful reflective response from a number of side directions, but there is great variation in response to the various different directions.
The present invention, in addressing this problem, now enables substantially equally or omnidirectionally efficient reflective response, and with improved efficacy.